The present invention relates to a process for chip forming, cutting or abrasive working of metals with the use of a cooling lubricant containing a fluorochlorohydrocarbon, to a cooling lubricant suitable for the process and also to a process for the preparation of such a cooling lubricant.
Chip forming, cutting or abrasive working of metals, in other words, metal working processes such as, for example, drilling, cutting, stamping, milling, turning, grinding, are carried out in the presence of cooling lubricants. According to one process disclosed in German Auslegeschrift No. 21 00 757, a cooling lubricant consisting of or containing trichloromonofluoromethane is used. In a variant of the process, this cooling lubricant may contain further compounds, but no such compounds are listed individually or as classes of chemical substances. It is therefore left to the knowledge of a person of ordinary skill in the art to make a selection from known additives. Thus, from U.S. Pat. No. 3,129,182 a cooling lubricant based on 1,1,2-trichloro-1,2,2-trifluoroethane is known, which contains as an additive ethyleneglycol monobutylether. German Offenlegunsschrift No. 21 00 735 and British Pat. No. 1,272,548 disclose nitroalkanes with 1 to 2 carbon atoms as aditives for 1,1,2-trichloro-1,2,2-trifluoroethane. Further, from U.S. Pat. No. 3,909,431 a cooling lubricant is known based on fluorochlorohydrocarbon (hereafter FCH) which contains cyclohexanone as an additive.
According to the state of the art, either pure FCH is employed as the cooling lubricant, which however, by itself often does not yield satisfactory results, or FCH is used with additives, which may be objectionable in view of their toxicity. Thus, for example, the maximum concentration value for the workplace (MWC value) for ethyleneglycol monobutylether and cyclohexanone is set at 50 ppm, and when using these additives, the permissible MWC values are easily exceeded. Furthermore, the skin- and mucosa-irritating effects and the liver- and kidney-damaging effects of cyclohexanone are known, and health-related objections exist for ethyleneglycol monobutylether, particularly in view of its ready absorption through the skin.